[Bug c/45493] New: -Wuninitialized does not warn

[tadhunt at gmail dot com]

When the first use of an uninitialized variable is inside a loop, no warning is
generated when -Wuninitialized is turned on.

int
main(void)
{
int len, i;

for(i = 0; i < 5; i++) {
printf("%d\n", len);// no warning!
len = 10;
}

return 0;
}


-- 
   Summary: -Wuninitialized does not warn
   Product: gcc
   Version: 4.4.1
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: c
AssignedTo: unassigned at gcc dot gnu dot org
    ReportedBy: tadhunt at gmail dot com
 GCC build triplet: x86_64-linux-gnu
  GCC host triplet: x86_64-linux-gnu
GCC target triplet: x86_64-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45493

[Bug c/45493] -Wuninitialized does not warn

[tadhunt at gmail dot com]

--- Comment #1 from tadhunt at gmail dot com  2010-09-02 03:42 ---
Same behavior on 4.4.3 & 4.4.1 (same host, target & build)

Forgot to mention:

gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5) 
gcc version 4.4.1 (Ubuntu 4.4.1-4ubuntu9) 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45493

[Bug c/42884] GCC (v4.3.3) fails to detect uninitialized variable

[tadhunt at gmail dot com]

--- Comment #19 from tadhunt at gmail dot com  2010-09-02 16:01 ---
This flamewar in the comments is hilarious.

To all concerned, here is a much simpler example.  This does appear to be a
regression.  I apologize that I cannot help fix it, as it's a really useful
feature that helps catch bugs.  Hat's off to you folks working hard on gcc.

int
main(void)
{
int len, i;

for(i = 0; i < 5; i++) {
printf("%d\n", len);// no warning!
len = 10;
}

return 0;
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42884

[Bug c/45493] -Wuninitialized does not warn

[tadhunt at gmail dot com]

--- Comment #3 from tadhunt at gmail dot com  2010-09-02 16:08 ---
(In reply to comment #2)

Richard, thanks for the confirmation.

This is a great feature that we've come to rely on over the years for catching
rookie errors.

This might not appear in comments very often, but I appreciate the hard work
you and the rest of the gcc folks put in.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45493